The field of the invention relates generally to power conversion systems, and more specifically, to improving load transient response in power conversion systems.
Rectifiers that employ a boost and buck converter architecture or a power factor correction (PFC) circuit and an inductor-inductor-capacitor (LLC) converter architecture are popular because of their flexibility, range of operation, and ability reach higher overall efficiency. Each converter has its own controller, typically including multiple cascaded control loops for output voltage, input current, and an outer boost voltage loop. During a fast load transient, it is important to coordinate all these loops across voltage boundaries to minimize output voltage fluctuation.
At least some known rectifiers include a single controller having isolated analog and digital inputs and outputs to maintain regulation across high voltage boundaries. Such rectifiers demand more expensive digital controllers and increase an overall part count and cost, which often lack the response time necessary for proper power converter operation. Other rectifiers use disturbance rejection methods that implement more complex algorithms that require more expensive controllers and/or more parts. Many of such methods also make the output control more susceptible to measurement noise.